Superradiance in a dense open Λ-system

Jamal T. Manassah, Barry M. Gross

Hichem Eleuch, I. Rotter

Evgenii Dmitrievich Trifonov, А. И. Зайцев, R. F. Malikov

M. T. Turaev, FRANK J. CROWNE

Mathias Hayn, Clive Emary, Tobias Brandes

We consider an ensemble of three-level particles in Lambda configuration interacting with two bosonic modes. The Hamiltonian has the form of a generalized Dicke model. We show that in the thermodynamic limit this model supports a superradiant quantum phase transition. Remarkably, this can be both a first- and a second-order phase transition. A connection of the phase diagram to the symmetries of the Hamiltonian is also given. In addition, we show that this model can describe atoms interacting with an electromagnetic field in which the microscopic Hamiltonian includes a diamagnetic contribution. Even though the parameters of the atomic system respect the Thomas-Reiche-Kuhn sum rule, the system still shows a superradiant phase transition.

E. R. Golubyatnikova, Vitalii V Kocharovskii, Vladimir V Kocharovskii

Mode superradiance (i.e. superfluorescence) in an open Fabry—Perot resonator is characterised by simultaneous emission of counterpropagating coherent pulses even when the mirrors have very low (but finite) reflection coefficients, beginning from R cr ≪ 1. It is shown that for any value of the resonator Q factor, even when R ≫ R cr or R ~ 1, a self-matched λ /2 grating of the population inversion in a two-level medium does not result in significant Bragg reflection which would exceed the reflection from the mirrors. A consistent allowance for the interference of inhomogeneous conterpropagating waves significantly alters the spatial and temporal dynamics of depletion of the population inversion and, consequently, greatly changes he profile of collective spontaneous radiation pulses, compared with the predictions of the mean field and unidirectional superradiance theories. A new nonlinear equation for superradiance in an open resonator is derived.